Bluetooth specification: v4.1
buletooth profile: support a2dp1.2/avrcp1.4/hfp1.6/hsp1.2
drive dimension:40mm
impedance:32 om
voltage:3.3-4.2v
frequency range:20-20000hz
rf range: 10m
s/n:>75db
distortion:<0.5%
playback time:>=16 hours
charging time:<=2.5 hours
built-in lithium battery: 3.7v/400mah